What is the meaning of the LED on the SFP and the Ethernet side?
On the side of the SFP are three LED:
SFP ACT: SFP Activity ( data is transmitted).
SFP LINK: Fiber is attached.
Some yellobriks have ethernet RJ-45 Sockets:
ETH Link (green) | ETH Activity (yellow) || ETH Link (green) | ETH Activity (yellow)
This is valid for the devices Oxx15x0 (e.g. OET1510).